Abstract: The present invention relates to a steel composition comprising, in percentages by weight of the total composition: Carbon: 0.06-0.20 preferably 0.08-0.18; Chromium: 2.5-5.0, preferably 3.0-4.5; Molybdenum: 4.0-6.0; Tungsten: 0.01-3.0; Vanadium: 1.0-3.0, preferably 1.5-2.5; Nickel: 2.0-4.0; Cobalt: 9.0-12.5, preferably 9.5-11.0; Iron: remainder as well as the inevitable impurities, optionally further comprising one or more of the following elements: Niobium: ?2.0; Nitrogen: ?0.50, preferably ?0.20; Silicon: ?0.70, preferably 0.05-0.50; Manganese: ?0.70, preferably 0.05-0.50; Aluminum: ?0.15, preferably ?0.10; the combined niobium+vanadium content being in the range 1.0-3.5; and the carbon+nitrogen content being in the range 0.06-0.50. It further relates to method of manufacture thereof, the steel blank obtained and a mechanical device or an injection system comprising same.

Abstract: The present invention relates to a steel composition carburizable and/or nitritable, comprising, in percentages by weight of the total composition: Carbon: 0.05-0.40, preferably 0.10-0.30; Chromium: 2.50-5.00, preferably 3.00-4.50; Molybdenum: 4.00-6.00; Tungsten: 0.01-1.80, preferably 0.02-1.50; Vanadium: 1.00-3.00, preferably 1.50-2.50; Nickel: 2.00-4.00; Cobalt: 2.00-8.00, preferably 3.00-7.00; Iron: balance as well as the inevitable impurities, optionally further comprising one or more of the following elements: Niobium: ?2.00; Nitrogen: ?0.50, preferably ?0.20; Silicon: ?0.70, preferably 0.05-0.50; Manganese: ?0.70, preferably 0.05-0.50; Aluminum: ?0.15, preferably ?0.10; the combined niobium+vanadium content being in the range 1.00-3.50; and the carbon+nitrogen content being in the range 0.05-0.50. It further relates to the method of production thereof, the steel blank obtained and a mechanical device comprising the latter.

Abstract: The present invention relates to a steel composition carburizable and/or nitritable, comprising, in percentages by weight of the total composition: Carbon: 0.05-0.40, preferably 0.10-0.30; Chromium: 2.50-5.00, preferably 3.00-4.50; Molybdenum: 4.00-6.00; Tungsten: 0.01-1.80, preferably 0.02-1.50; Vanadium: 1.00-3.00, preferably 1.50-2.50; Nickel: 2.00-4.00; Cobalt: 2.00-8.00, preferably 3.00-7.00; Iron: balance as well as the inevitable impurities, optionally further comprising one or more of the following elements: Niobium: ?2.00; Nitrogen: ?0.50, preferably ?0.20; Silicon: ?0.70, preferably 0.05-0.50; Manganese: ?0.70, preferably 0.05-0.50; Aluminum: ?0.15, preferably ?0.10; the combined niobium+vanadium content being in the range 1.00-3.50; and the carbon+nitrogen content being in the range 0.05-0.50. It further relates to the method of production thereof, the steel blank obtained and a mechanical device comprising the latter.

Abstract: A carburisable steel alloy suitable for bearing components comprising, in percent by weight: C 0.05-0.5 wt. % Cr 2.5-5.0 wt. %, Mo 4-6 wt. %, W 2-4.5 wt. %, V 1-3 wt. %, Ni 2-4 wt. %, Co 2-8 wt. %, optionally one or more of the following elements: Nb 0-2 wt. % N 0-0.5 wt. % Si 0-0.7 wt. %, Mn 0-0.7 wt. %, Al 0-0.1 5 wt. %, wherein the combined amount of Nb+V is within the range 1-3.5 wt. %, the combined amount of C+N is within the range 0.05-0.5 wt. %, the balance being Fe and unavoidable impurities.

Abstract: A carburisable steel alloy suitable for bearing components comprising, in percent by weight: C 0.05-0.5 wt. % Cr 2.5-5.0 wt. %, Mo 4-6 wt. %, W 2-4.5 wt. %, V 1 -3 wt. %, Ni 2-4 wt. %, Co 2-8 wt. %, optionally one or more of the following elements: Nb 0-2 wt. % N 0-0.5 wt. % Si 0-0.7 wt. %, Mn 0-0.7 wt. %, Al 0-0.1 5 wt. %, wherein the combined amount of Nb+V is within the range 1 -3.5 wt. %, the combined amount of C+N is within the range 0.05-0.5 wt. %, the balance being Fe and unavoidable impurities.

Abstract: A method for manufacturing by powder metallurgy a steel part is provided. A pre-alloyed powder is prepared, having the desired composition for said part, except for the O and N contents and optionally C contents, with O and N contents of at most 200 ppm, and with an Mn content from 0.

Abstract: Steel for the manufacture of a component for bearings, the chemical composition of which comprises, by weight: 0.6%≦C≦1.5%; 0.4%≦Mn≦1.5%; 0.75%≦Si≦2.5%, 0.2%≦Cr≦2%; 0%≦Ni≦0.5%; 0%≦Mo≦0.2%; 0%≦Al≦0.05%; S≦0.04%; the balance being iron and impurities resulting from smelting and the composition furthermore satisfying the relationships: Mn≦0.75+0.55×Si and Mn≦2.5−0.8×Si. Process for the manufacture of a bearing component.

Abstract: Steel for the manufacture of a component for bearings, the chemical composition of which comprises, by weight: 0.6%≦C≦1.5%; 0.4%≦Mn≦1.5%; 0.75%≦Si≦2.5%; 0.2%≦Cr≦2%; 0%≦Ni≦0.5%; 0%≦Mo≦0.2%; 0%<Al≦0.05%; S≦0.04%; the balance being iron and impurities resulting from smelting and the composition furthermore satisfying the relationships: Mn≦0.75+0.55×Si and Mn≦2.5−0.8×Si. Process for the manufacture of a bearing component.

Abstract: Steel for the manufacture of a component for bearings, the chemical composition of which comprises, by weight: 0.6%.ltoreq.C.ltoreq.1.5%; 0.4%.ltoreq.Mn.ltoreq.1.5%; 0.75%.ltoreq.Si.ltoreq.2.5%; 0.2%.ltoreq.Cr.ltoreq.2%; 0%.ltoreq.Ni.ltoreq.0.5%; 0%.ltoreq.Mo.ltoreq.0.2%; 0%<Al.ltoreq.0.05%; S.ltoreq.0.04%; the balance being iron and impurities resulting from smelting and the composition furthermore satisfying the relationships: Mn.ltoreq.0.75+0.55.times.Si and Mn.ltoreq.2.5-0.8.times.Si. Process for the manufacture of a bearing component.

Abstract: Steel chemical composition of which contains, by weight: 0.1%.ltoreq.C.ltoreq.0.4%; 1%.ltoreq.Mn.ltoreq.1.8%; 0.15%.ltoreq.Si.ltoreq.1.7%; 0%.ltoreq.Ni.ltoreq.1%; 0%.ltoreq.Cr.ltoreq.1.2%; 0%.ltoreq.Mo.ltoreq.0.3%; 0%.ltoreq.V.ltoreq.0.3%; Cu.ltoreq.0.35%; optionally from 0.005% to 0.06% of aluminum, optionally boron in contents of between 0.0005% and 0.01%, optionally between 0.005% and 0.03% of titanium, optionally between 0.005% and 0.06% of niobium, optionally from 0.005% to 0.1% of sulfur, optionally up to 0.007% of calcium, optionally up to 0.03% of tellurium, optionally up to 0.05% of selenium, optionally up to 0.05% of bismuth, optionally up to 0.1% of lead, the balance being iron and impurities resulting from smelting. Process for the manufacture of a forging.

Abstract: Steel useful for the manufacture of a separable mechanical component, whose chemical composition preferably comprises, by weight: 0.25%.ltoreq.C.ltoreq.0.75%, 0.2%.ltoreq.Si.ltoreq.1.5%, 0.1%.ltoreq.Mn.ltoreq.2%, 0%.ltoreq.Ni.ltoreq.1%, 0%.ltoreq.Cr.ltoreq.1%, 0%.ltoreq.Mo.ltoreq.1%, 0%.ltoreq.Cu.ltoreq.1%, 0%.ltoreq.V.ltoreq.0.2%, 0.02%.ltoreq.S.ltoreq.0.35%, 0.04%.ltoreq.P.ltoreq.0.2%, 0%.ltoreq.Al.ltoreq.0.005%, 0.005%.ltoreq.N.ltoreq.0.02%; optionally at least one element taken from lead, tellurium and selenium in contents of less than 0.1%, the balance being iron and impurities resulting from the smelting, the steel being optionally treated with calcium. Use of the steel for the manufacture of a separable component and component obtained.

Abstract: Steel for the manufacture of forgings having a bainitic structure and the mechanical properties of which are: R.sub.p0.2 .gtoreq.800 MPa, R.sub.m .gtoreq.1000 MPa, K.sub.cu .gtoreq.50 J/cm.sup.2 its chemical composition comprising, by weight: 0.05%.ltoreq.C.ltoreq.0.12%, 0.1%.ltoreq.Si.ltoreq.0.45%, 1.01%.ltoreq.Mn.ltoreq.1.8%, 0.15%.ltoreq.Cr .ltoreq.1.15%, 0.06%.ltoreq.Mo.ltoreq.0.12%, Cu.ltoreq.0.30%, Ni.ltoreq.0.30%, 0.01%.ltoreq.Ti.ltoreq.0.04%, 0.005%.ltoreq.Al.ltoreq.0.04%, 0.006%.ltoreq.N.ltoreq.0.013%, 0.0005% 5 B.ltoreq.0.004%, P.ltoreq.0.025%, 0.02%.ltoreq.S.ltoreq.0.1%, 0%.ltoreq.Pb.ltoreq.0.1%, 0%.ltoreq.Te.ltoreq.0.07%, optionally from 0.0002% to 0.002% of calcium, the balance being iron and impurities resulting from the smelting, the chemical composition furthermore satisfying the relationship: 0.2% .ltoreq.Ni+Mo+Cu.ltoreq.0.7%, the uncombined boron content not being less than 0.0005% above 950.degree. C. Process for the manufacture of a forging.

Abstract: The invention relates to a method for fabricating a piece of structural steel that includes thermal or thermomechanical treatment steps that could ordinarily lower the fatigue strength and shock and impact resistance of the steel piece. In the method of the invention a workpiece of microalloy steel is fabricated containing the following elements in the mounts indicated and having a bainitic structure:______________________________________ C 0.05-0.5 wt. % Mo 0-0.5 wt. % Mn 1-2 wt. % V 0-0.30 wt. % Si 0.05-1.5 wt. % B 0-0.010 wt. % Cr 0.1-1 wt. % Ti 0-0.030 wt. % Nb 0-0.1 wt. % ______________________________________The workpiece is then subjected to a treatment that includes a heating stage wherein at least a part of said piece is subjected to a temperature in the range 500.degree.-900.degree. C., followed by a cooling stage in which at least the part of the piece is subjected to cooling at a rate greater than 500.degree. C./hr.